Improvement in key-hole guard for door-locks



D. A. PRATT, OF `SING SING, NEW YORK.

IMPROVEMENT IN KEY-HOLE GUARD FOR DOOR-LOCKS.

Specification forming part of Letters Patent No. 69,700, dated October 8, 1867.

To all whom it may concern:

.Be it known that I, D. A. PRATT, of Singy Sing, Westchester county, and Stateof New York, have invented a new and Improved Travelers Universal Safety-Key; and I do hereby declare that the following is a full,

clear, and exact description thereof, which will enable those skilled in the art to make and 'use the same, reference being had to the accompanying drawings, forming part of this specification, in whichl Figure 1 is an external view when closed or in a state of rest or non-use. Fig. 2 is an external View when fully opened or in use. Fig. 3 is a detached vertical inside view of the cam 7 or screw by means of which the key is operated or changed from Fig. l to Fig. 2. Fig. 4 is a door-lock with the key inserted in the key-hole thereof, and partially opened, per forming its functions.

Object.

The object of this invention is to furnish travelers with a single key of almost universal application to every room they may occupy duringv their journey, and by the use of which every such door or lock maybe rendered burglar-proof while the occupant is asleep or within, as against every known mode of burglarious operation except absolute and extensive violence.

lt is well known that burglars seldom or never, unless on being discovered, use violence or make anynoise. Their first plan is to id,r some window open or door ajar. Failing to find these, the forceps,7 false or skeleton 7 keys, or the wires are their only remaining chances. Consequently, if we can head them oi in the use of all of these their occupation is gone, except as the highwayman, by actual force and open threats.

How Used.

Its mode or manner of use is simply to fill up the key-hole of the lock by some immova# ble obstruction, as follows: First, lock the door of said room from the inside with the key that belongs to it, and take the key out.

Then, having screwed the travelers key intoV hole being filled, he has no chance to commence any operation other than that of violence, which at once warns the inmate.

How Made.

The key is made of four parts or pieces, and may be 'made of brass, steel, or iron.

The arbor a in Fig. 2 may be of any de sired size and length, and made of solid metal, either cutting or molding its slots and grooves, or be struck up 7 out of sheet metal.

The serrated arm b and levered lip c, same ligure, should be of sheet-steel or hammered brass, and be proportioned in size and length to the arbor a'.

The cam d, Fig. 3, and d, Figs. 1, 2, and 4, has a V-shaped spiral thread on its inner surface, as seen in Fig. 3and revolves upon the arbor c, acting as a screw upon the arm b, which, in turn, acts upon the levered lip c,

thus serving at will to expand or contract the dimensions of the movable or operating parts of the key, in order that one or both of them may catch against the inner parts of the lock, and thus prevent its being turned in the lock by forceps, in order to throw the bolt back, or be pushed out ot the lock in order to insert a skeleton, or for the manipulation of picks.

Further description is deemed unnecessary, since the drawings fully explain themselves, except to say that the serrated end of the arm b may be attached to the power end of the levered lip c, and worked, as in this case, in a perpendicular line with the key-hole of the lock, or horizontally therewith; or two such levered lips, working horizontally with the key-hole, and in opposite directions on the same or on different fulcra, may be used and operated by one cam.

Ola/im.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

The V-shapcd cam or spiral screw, revolving on the arbor a of the key, forthe purposes of expanding or contracting the arm b or lip c; also the serrated arm b, as well as the combination of said serrated arm b and lip c with said cam.

D. A. PRATT. Witnesses:

ABEAM REQUE, SELAH REEVE. 

